Exhaust Conversion (LX/DX/CX/HX to EX) (96-00 Civic)
 

Attachment 22201


My header was really close to touching the tranny mount bracing so i took the lower midpipe off the header and grinded a bit of the brace down a bit so it will clear, that way i dont have to worry about any rattling noises. it might have been ok but i wasnt taking a chance. your header might fit better so this might not pertain to your swap/upgrade.

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Now your header is firmly mounted to the head.... now if you dont care about mother nature of being legal then you COULD simply bolt the header up to your stock DX midpipe BUT YOU WILL HAVE A CEL LIGHT, IT WILL BE ILLEGAL AND WILL NOT PASS SMOG TESTS OR EVEN VISUAL INSPECTION. AND IF YOU DO NOT USE SOME KIND OF O2 ELIMINATOR IT WILL PUT YOUR CAR IN LIMP MODE WHICH WILL KILL YOUR PERFORMANCE AND BE A TOTAL WASTE.... needless to say go the extra mile and be nice to mother earth and keep the car legal!




Now that your going to keep your car legal and emission friendly lets continue....

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Put the new gasket on the rear of the header and bolt the catalytic converter to the header. i did not use the factory spring bolts because I HATE THEM!!!!!! ive always had issues with them so i bolted it solid.

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O YA if your reusing your DX mid pipe be sure to cut it down close to the length of the converter.
OR if your upgrading your cat back exhaust with a EX cat back exhaust then youll be able to simply bolt the converter up and your done with all the hard work!

Attachment 22210



I was cheap and modified my DX piping to fit my EX header system... biggest problem NO ONE SELLS THIS FLANGE!!!!!!!! but i was lucky enough that my local muffler shop had some ones old rusted off flange laying around the scrap pile and he just gave it to me. so i wire brushed it on the bench so i could weld to it... ya my welds sucked but i was in a hurry to get done and figured i could always just buy a cat back system later on for the mid pipe since i still want to keep my stock muffler.
anyways i welded a exhaust adapter to the old flange and then sliped it onto the stock piping, gave it afew tach welds with it on the car THEN i got lazy and instead of pulling the whole mid pipe off to weld it solid i just went back to autozone to return the O2 socket set and pick up a few simple clamps. then i just clamped the adaptor to the stock piping..... so far no leaks so no need to remove the whole mid pipe off the car and weld it solid.

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now that your piping is all bolted up your golden! only thing to do now is plug in the O2 extenders and plug them into your O2 sensors.
some simple routing the wires free from moving parts and heat sources.
Also when i installed my extender wires they pluged into the senors with ease BUT when pluging them into the engine harness they where a PITA!!!!!! took alot of force to get them plugged in and i had to use a pair of pliers to get the plugs the rest of the 1/4inch in together. after i got them all plugged in firmly i fired up the motor and so far free from CEL troubles. tho i have not had a chance to drive the car yet. i quite for the night. but if it has not came on yet then im pretty sure it wont come on later.
and no leaks so far.
and i used all new OEM gaskets. new gasket ring on the convter and head/header, and donute gasket on the header/cat.

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AND NOW YOU HAVE A NICE LOOKING, EASY BREATHING EXHAUST...

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FINALLY Be sure to re-torque the bolts at the head and midway flange after you use it once and let it cool down all the way.
END..........

Attachment 22185


My header was really close to touching the tranny mount bracing so i took the lower midpipe off the header and grinded a bit of the brace down a bit so it will clear, that way i dont have to worry about any rattling noises. it might have been ok but i wasnt taking a chance. your header might fit better so this might not pertain to your swap/upgrade.

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Now your header is firmly mounted to the head.... now if you dont care about mother nature of being legal then you COULD simply bolt the header up to your stock DX midpipe BUT YOU WILL HAVE A CEL LIGHT, IT WILL BE ILLEGAL AND WILL NOT PASS SMOG TESTS OR EVEN VISUAL INSPECTION. AND IF YOU DO NOT USE SOME KIND OF O2 ELIMINATOR IT WILL PUT YOUR CAR IN LIMP MODE WHICH WILL KILL YOUR PERFORMANCE AND BE A TOTAL WASTE.... needless to say go the extra mile and be nice to mother earth and keep the car legal!




Now that your going to keep your car legal and emission friendly lets continue....

Attachment 22191


Put the new gasket on the rear of the header and bolt the catalytic converter to the header. i did not use the factory spring bolts because I HATE THEM!!!!!! ive always had issues with them so i bolted it solid.

Attachment 22192

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O YA if your reusing your DX mid pipe be sure to cut it down close to the length of the converter.
OR if your upgrading your cat back exhaust with a EX cat back exhaust then youll be able to simply bolt the converter up and your done with all the hard work!

Attachment 22194



I was cheap and modified my DX piping to fit my EX header system... biggest problem NO ONE SELLS THIS FLANGE!!!!!!!! but i was lucky enough that my local muffler shop had some ones old rusted off flange laying around the scrap pile and he just gave it to me. so i wire brushed it on the bench so i could weld to it... ya my welds sucked but i was in a hurry to get done and figured i could always just buy a cat back system later on for the mid pipe since i still want to keep my stock muffler.
anyways i welded a exhaust adapter to the old flange and then sliped it onto the stock piping, gave it afew tach welds with it on the car THEN i got lazy and instead of pulling the whole mid pipe off to weld it solid i just went back to autozone to return the O2 socket set and pick up a few simple clamps. then i just clamped the adaptor to the stock piping..... so far no leaks so no need to remove the whole mid pipe off the car and weld it solid.

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now that your piping is all bolted up your golden! only thing to do now is plug in the O2 extenders and plug them into your O2 sensors.
some simple routing the wires free from moving parts and heat sources.
Also when i installed my extender wires they pluged into the senors with ease BUT when pluging them into the engine harness they where a PITA!!!!!! took alot of force to get them plugged in and i had to use a pair of pliers to get the plugs the rest of the 1/4inch in together. after i got them all plugged in firmly i fired up the motor and so far free from CEL troubles. tho i have not had a chance to drive the car yet. i quite for the night. but if it has not came on yet then im pretty sure it wont come on later.
and no leaks so far.
and i used all new OEM gaskets. new gasket ring on the convter and head/header, and donute gasket on the header/cat.

Attachment 22199

AND NOW YOU HAVE A NICE LOOKING, EASY BREATHING EXHAUST...

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FINALLY Be sure to re-torque the bolts at the head and midway flange after you use it once and let it cool down all the way.
END..........

this is a great detailed write up
i'm gonna add it to the DIY I made right away

you may want to add to the end of the DIY about re-torquing the bolts at the head and midway flange after you use it once and let it cool down all the way

o ya THANKS. i almost forgot that...

ok... today took it for a drive and still no CEL light so that is great!!!!!! only downfall is i have a pinhole leak somewhere (most likely my mounting flange or weld to the flange or maybe on the clamp... its only a pinhole and only noticable at higher rpms. just a chance i took with modifying the dx midpipe... o well ill fix it!

not sure if its just me or not but it does feel better on the butt dyno ;)

i just have to pull the car back out in the shop and torque everything back down again and remove the midpipe to just weld it all solid.... ill probably do that friday since im off work.

Ok I know I asked about the o2 wire extentions already but... Did you use the extentions for both the o2 sensors or just the one located on the cat? If you did both o2 sensors then why, is there a reason for this? My header has 2 o2 bungs. I was going to plug the back one and use the bung located on the first header tube for the the first 02. If I did this I would only need the longer o2 extention right?

i put them in the proper EX position... the primary in the heades rear and the one on the ex cat. i didnt want to put it in the front since well the sensor mounting in front is ugly anyays. ;)
so i used the long one for the rear cat sensor and the short one for the rear header sensor.

Ok that what I figured you did. I will try extending only the o2 sensor on the cat and see if that works. I am trying to be as cheap as possible with this swap, but I want to do it right the first time. I will post up my swap as well once I get to. It will be a few weeks though as I am saving money to get a cat back made at the same it. Thanks bass once again.

no problem. good luck with the swap. its definatly not hard.. and as long as you use decent parts it should bolt up pretty easily.

Yeah I know I have done a few IHE in my time. I got my header in. I went with the ebay one so we will see. As far as quality it looks good, nice clean welds and good bends. The only thing I have picked out so far with the get what you for header is, it is painted grey not ceramic coated. I left a bad review about that. We will see if it fits ok. I am bidding on a magnaflow cat rigt now :) Could you get some pics of your wire extention and how you routed it? Also what size nuts are needed for the studs on the head? Thanks.